This proposal involves a multi-disciplinary/multi-professional research approach to pediatric malignancies with special emphasis on chemotherapy in acute leukemias, and in solid tumor, special emphasis is given to the interdigitation of chemotherapy with other modalities of therapy, such as radiation therapy and surgery. Specific studies of chemo-immunotherapy have been recently activated. The vast majority of these studies are conducted in cooperation with protocols generated through the SWOG. Members of the Pediatric Oncology Team at Children's Memorial Hospital in Oklahoma City not only contribute their patients to SWOG protocols, but are actively involved in protocol design, writing of protocols, evaluating group studies, and serving in an administrative capacity in general group support. Our Pediatric Oncology Team also participates in national cooperative studies, and interinstitutional studies. When patients are not eligible for SWOG or national protocols, independent pilot studies are undertaken in an attempt to gain preliminary data that can be helpful in the design of future group studies. This research proposal is the main stay in our management of pediatric malignancies and allows us to cooperate in SWOG and national studies. Additional independent cancer research which is dependent upon our primary patient population includes studies in: 1) serum factors that inhibit lymphocyte transformation, 2) pilot studies in immunotherapy with either transfer factor or non-specific immune stimulation, 3) bone marrow transplantation, etc. Bibliographic references: Sullivan, M.P., Humphrey, G.B., Vietti, T.J., Haggard, M.E., Lee, E.: Superiority of conventional intrathecal methotrexate therapy with maintenance over intensive intrathecal methotrexate therapy, involvement of radiotherapy (2,000-2,500 rads neuroaxis) in treating meningeal leukemia. Cancer 35:1066-1073, 1975. Hoge, A.F., Humphrey, G.B.: Towards control of breast cancer in Oklahoma. Oklahoma State Med. J., 68:8-12, January, 1975.